Gear drive

ABSTRACT

A drive assembly for powered equipment includes a housing having a gear drive disposed therein, with an input shaft extending into the housing and having a first end engaged to and powering the gear drive, and an output shaft powered by the gear drive. The output shaft extends out of the housing and has an axis of rotation that is perpendicular to the axis of rotation of the input shaft. A support shaft for one of the gears in the gear drive is also located in the housing, where the support shaft has a longitudinal axis that is perpendicular to both the input shaft and the output shaft.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.13/567,704 filed on Aug. 6, 2012, which is a continuation of U.S. patentapplication Ser. No. 12/830,130 filed on Jul. 2, 2010, now U.S. Pat. No.8,235,858, which claims the benefit of U.S. Provisional PatentApplication No. 61/222,562 filed on Jul. 2, 2009. The terms of all ofthe foregoing applications are incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

This invention relates to a gear drive assembly for use in driving, forexample, an auger for a snow thrower.

SUMMARY OF THE INVENTION

An improved gear drive assembly is disclosed herein, including gearreduction assemblies to provide for a less expensive, lighter and morecompact unit.

The present invention comprises a gear drive assembly for use in autility vehicle or other power equipment. A compact gear drive assemblyfor powered equipment includes a housing having a first tubularextension, and an input shaft having a first end located in the housingand a second end extending from the housing through the first tubularextension. The gear drive assembly further includes a first stage gearreduction engaged to and driven by the first end of the input shaft, asecond stage gear reduction engaged to and driven by the first stagegear reduction, and an axle engaged to and driven by the second stagegear reduction.

The gear drive assembly is shown in use with a snow thrower. While shownand described in reference to utility vehicles, it will be apparent tothose skilled in the art that the gear drive assembly defined hereincould be utilized in a variety of other configurations or applicationsthat require transfer of mechanical power from a prime mover, eitherdirectly or indirectly, through a compact gear drive assembly.

In one aspect of the invention, the two-stage gear reduction includestwo bevel gear reductions. In another aspect of the invention, thetwo-stage gear reduction includes a first stage bevel gear reduction anda second stage planetary gear reduction.

A better understanding of the objects, advantages, features, propertiesand relationships of the invention will be obtained from the followingdetailed description and accompanying drawings which set forthillustrative embodiments that are indicative of the various ways inwhich the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a snow thrower incorporating afirst embodiment of a gear drive assembly in accordance with theprinciples of the present invention.

FIG. 2 is a perspective view of the gear drive assembly in accordancewith the first embodiment.

FIG. 3 is an exploded perspective view of the gear drive assembly ofFIG. 2.

FIG. 4 is a further exploded perspective view of certain gearingcomponents and a housing element of the gear drive assembly of FIG. 2.

FIG. 5 is a side elevational view of a snow thrower incorporating asecond embodiment of a gear drive assembly in accordance with theprinciples of the present invention.

FIG. 6 is a perspective view of the gear drive assembly in accordancewith the second embodiment.

FIG. 7 is an exploded perspective view of the gear drive assembly ofFIG. 6.

FIG. 8 is a further exploded perspective view of certain gearingcomponents of the gear drive assembly of FIG. 6.

FIG. 9 is a perspective view of a gear drive assembly in accordance witha third embodiment of the present invention.

FIG. 10 is a perspective view of a gear drive assembly in accordancewith a fourth embodiment of the present invention.

FIG. 11 is an exploded perspective view of certain gearing componentsand a housing element of the gear drive assembly of FIG. 10.

FIG. 12 is a perspective view of an output shaft, a gear support shaft,and a T-bushing element of the gear drive assembly of FIG. 10.

FIGS. 13 and 14 are perspective views of the T-bushing element of FIG.12.

DETAILED DESCRIPTION OF THE DRAWINGS

The description that follows describes, illustrates and exemplifies oneor more embodiments of the present invention in accordance with itsprinciples. This description is not provided to limit the invention tothe embodiments described herein, but rather to explain and teach theprinciples of the invention in order to enable one of ordinary skill inthe art to understand these principles and, with that understanding, beable to apply them to practice not only the embodiments describedherein, but also other embodiments that ma come to mind in accordancewith these principles. The scope of the present invention is intended tocover all such embodiments that may fall within the scope of theappended claims, either literally or under the doctrine of equivalents.

It should be noted that in the description and drawings, like orsubstantially similar elements may be labeled with the same referencenumerals. However, sometimes these elements may be labeled withdiffering numbers, such as, for example, in cases where such labelingfacilitates a more clear description. Additionally, the drawings setforth herein are not necessarily drawn to scale, and in some instancesproportions may have been exaggerated to more clearly depict certainfeatures. Such labeling and drawing practices do not necessarilyimplicate an underlying substantive purpose. As stated above, thepresent specification is intended to be taken as a whole and interpretedin accordance with the principles of the present invention as taughtherein and understood by one of ordinary skill in the art.

Vehicle 100, shown in FIG. 1 as a snow thrower, includes a prime moversuch as engine 101 mounted on vehicle frame 102 and an auger 107 used tofeed snow to a blower device (not shown). Engine 101 powers a drive beltand pulley system 103 to power both transaxle 108 and gear driveassembly 110, as described in more detail herein. Transaxle 108 may beof various known types, and it will not be described in detail herein. Asimilar transaxle design is shown in commonly-owned U.S. Pat. No.6,651,529, the terms of which are incorporated herein by reference.

Input shaft 112 of gear drive assembly 110 is engaged to belt and pulleysystem 103 by means of input pulley 104. Gear drive assembly 110includes a two-piece housing structure comprising main housing 120 andhousing cover 130 joined together by means of a series of fasteners 172,as shown most clearly in FIGS. 2 and 3. Disposed within the housing is agear assembly 140 which includes a pinion bevel gear 142 disposed on anend of input shaft 112 and engaged to and driving domed bevel gear 144.As seen most clearly in FIG. 4, nested bevel gear 146 is disposed ongear support shaft 152 and rotates with domed bevel gear 144 to driveoutput bevel gear 148, which is splined to tubular output shaft 150.Gear 144 may be engaged to gear 146 by means of a gear-form type ofinterface, as shown, or by other tight-fitting, known interface shapesand joining methods. The shape of domed bevel gear 144, as shown in FIG.4, permits bevel gear 146 to be disposed primarily inside the dome,providing an overlap, in the vertical direction, of bevel gear 144 andoutput bevel gear 148, thereby permitting a compact unit. Bevel gears142, 144, 146 and 148 form a two-stage gear reduction assembly.

Output shaft 150 is provided with keyway 151 to drive auger 107 or analternate device. Other known means of transferring such rotationalforce may be used in place of keyway 151. Plug 156 may be inserted orscrewed into an opening in main housing 120 in order to seal assembly110 after lubricant is added and also to retain shaft 152. Variousthrust washers, such as washers 162, 164 and 166, may be provided asneeded to prevent excessive wear which can be caused by gears runningagainst other components, such as housing components, for example.

A second embodiment gear drive assembly 210, for use on vehicle 200, isdepicted in FIGS. 5-8. Minor variations, such as in the size of frame202 and belt and pulley assembly 203, are required on vehicle 200 due todifferences between gear drive assembly 210 and the prior embodiment, asdetailed below. In an arrangement similar to that of previouslydescribed vehicle 100, input shaft 212 of gear drive assembly 210 isengaged to belt and pulley assembly 203 by means of input pulley 204.

A unique housing assembly is shown most clearly in FIGS. 6 and 7,wherein main housing 220 and housing cover 230 are connected by means ofa series of locking tabs 230 a engaging a corresponding series ofprojections 220 a. Other means of securing the housing elements such asfasteners, gluing or ultrasonic welding could also be used.

As shown in FIGS. 7 and 8, this embodiment includes gear assembly 240comprising bevel gear reduction as a first stage and planetary gearreduction as a second stage. This arrangement permits the use of plasticgears for certain applications, helping to reduce weight and cost. Ringgear 230 b is formed on an inside surface of housing cover 230 it willbe understood that ring gear 230 b could also be a separate element fromcover 230. Ring gear 230 b engages a plurality of planetary gears 282disposed on planetary gear carrier 280.

A pinion bevel gear 242 is disposed on input shaft 212 and drives bevelgear 244 a, which in this embodiment is shown integrally formed as partof combination gear 244 along with gear connecting member 244 c and sungear 244 b, so that sun gear 244 b rotates with bevel gear 244 a. Itwill be understood that gear elements 244 a, 244 b and 244 c could beformed as two or three separate elements secured together using knownmeans. Planetary gears 282, which rotate on pins 280 b on carrier 280,are driven by sun gear 244 b thereby transferring rotational force tocarrier 280, which applies rotational force to output shaft 250 by meansof splines 280 a on carrier 280 mating with splines 250 a on outputshaft 250. As before, output shaft 250 is engaged to the auger totransfer rotational force thereto, and various thrust washers such aswashers 262 and 266 may be provided as needed to reduce friction andwear. This arrangement permits a particularly compact gear drive unit;for example, when mounted in the vehicle, input shaft 212 is on the sameplane as output shaft 250. This arrangement may require alteration ofthe location of the blower device (not shown) of vehicle 200 as comparedto vehicle 100.

FIG. 9 shows yet another embodiment, gear drive assembly 310, wherehousing 120 and cover 330 are joined by fasteners 372 and the outputshaft comprises solid, shaft 350, input shaft 312 is partially supportedby tubular extension 320 b. An internal gear support shaft (not shown)is partially supported by tubular extension 320 a and is retained inhousing 320 by plug 356. A separate oil fill plug 332 is provided incover 330. Internal features (not shown) of the third embodiment may begenerally consistent with internal features of the fourth embodiment, asdescribed below.

A fourth embodiment, gear drive assembly 410, which may be used on avehicle similar to vehicle 100, is depicted in FIGS. 10-14.

Referring to FIG. 10, gear drive assembly 410 includes input shaft 412,housing 420 and cover 430, which are joined by fasteners 472, and outputshaft 450. As best seen in HG. 11, primarily disposed within housing 420is a gear assembly 440, which provides two successive bevel gearreductions. A first bevel gear reduction includes a pinion bevel gear442 disposed on an end of input shaft 412. Gear 442 drives a domed bevelgear 444. A domed flange bevel gear 446 is disposed on gear supportshaft 452 and is fixedly nested in domed bevel gear 444 to rotate inunison therewith to drive output bevel gear 448, which is coupled tooutput shaft 450. Gear 446 is press-fit into gear 444 and thenheat-treated so that a plurality of fingers 446 a of the domed flangeportion of gear 446 expand while a plurality of mating, slots 444 a ingear 444 contract so that the two gears are tightly locked as the twoparts grow together during heat-treating. Gear 446 may be engaged togear 444 as described or by other known tight-fit joining methods. Assuch, a second bevel gear reduction is provided by bevel gear 446 andoutput bevel gear 448. The shape of domed bevel gear 444 permits bevelgear 446 to be disposed primarily inside the dome and provides anoverlap of bevel gears 444 and 448 in the vertical direction, therebypermitting, a compact unit. As shown in FIG. 12, output shaft 450 isprovided with a key 458 configured to engage a keyway (not shown)provided in a circumferential surface of a central opening extendingthrough output bevel gear 448, so that bevel gear 448 is engaged to anddrives output shaft 450 during, operation. Revel gear 448 is restrainedfrom axial movement in one direction byT-bushing 454 and in the otherdirection by a retaining ring (not shown) which engages groove 450 a ofoutput shaft 450. Moreover, as is known to one of ordinary skill in theart, bevel gears 442 and 448, for example, can be fixedly attached torespective shafts 412 and 450 by various other known methods, such aspress-fitting, corresponding splined surfaces, setscrews, adhesives orother suitable means.

As shown in FIG. 10, housing 420 includes a tubular extension 420 a thataccommodates an upper portion of gear support shaft 452. Tubularextension 420 a includes an external opening for adding lubricant togear drive assembly 410, and plug, 456 serves to close the externalopening, and retain gear support shaft 452 shown in FIG. 11. Input shaft412 is rotatably supported in tubular extension 420 h of housing 420 bya bearing 460 that can withstand a radial load and a thrust load actingon input shaft 412. Bearing 460 may be any suitable bearing, such as,for example, an angular type bearing.

Now referring to FIGS. 11-14, a T-bushing 454 is provided withanti-rotation slots 454 a, a shaft support slot 454 b, and athrough-bore 454 c to accommodate output shaft 450. Through-bore 454 cdefines arm inner circumferential surface which is provided with one ormore lubrication grooves 454 d to facilitate the flow of a lubricant,such as oil, through 1′-bushing 454, thereby coating during operation atleast an adjacent external surface of rotating output shaft 450.Through-bore 454 c may also be lined with an anti-friction materialwhich can reduce wear on T-bushing 454 and on output shaft 450.Anti-rotation slots 454 a and support slot 454 b are arranged onopposite vertical sides of T-bushing 454, the vertical sides beingperpendicular to the axis of output shaft 450. Anti-rotation slots 454 aare configured to engage with tabs 430 a formed on an internal surfaceof housing cover 430, and U-shaped support slot 454 b is configured toaccommodate therein gear support shaft 452. When gear drive assembly 410is assembled, anti-rotation slots 454 a are mechanically locked to tabs430 a, thereby providing rigid support for shaft 452 and preventing thetwo-stage bevel gear reduction assembly 440 from rotating along withrotating output shaft 450 during operation. This rigid support functionprovided by T-bushing 454 facilitates proper gear meshing resulting innoise reduction, smooth operation and longer service life of gear driveassembly 410. As shown, T-bushing 454 includes an elongated verticalsupport slot 454 b to provide support for gear support shaft 452.Although two anti-rotation slots 454 a are shown in T-bushing 454, adifferent number of slots 454 a and a corresponding number of tabs 430 amay be provided.

Gear drive assembly 410 can be made of metallic and non-metallicmaterials. Metallic materials may include, but are not limited to,steel, stainless steel, anodized aluminum, aluminum, titanium,magnesium, brass, and their respective alloys. Non-metallic materials,suitable for housing 420, cover 430 and select rotating and non-rotatinginternal components for components example, may include, but are notlimited to, various plastic and polymeric compounds. Typical industrymethods of forming such metallic materials include various knowntechniques, such as casting, forging, shearing, bending, machining,riveting, welding, powdered metal processing, extruding, molding, andothers.

While specific embodiments of the invention have been described indetail, it will be appreciated by those skilled in the art that variousmodifications and alternatives to those details could be developed inlight of the overall teachings of the disclosure. Accordingly, theparticular arrangements disclosed are meant to be illustrative only andnot limiting as to the scope of the invention which is to be given thefull breadth of the appended claims and any equivalent thereof.

What is claimed is:
 1. A drive assembly for use in a vehicle having anengine and a separate transmission for driving the vehicle, the driveassembly comprising: a gear drive comprising a plurality of gearsdisposed in a housing; an input shaft extending into the housing andhaving a first end engaged to and powering the gear drive and a secondend operatively engaged to the engine, the input shaft having a firstaxis of rotation; an output shaft powered by the gear drive, the outputshaft having a second axis of rotation that is perpendicular to thefirst axis of rotation; and a support shaft for one of the plurality ofgears, the support shaft having a longitudinal axis that isperpendicular to the first axis of rotation and the second axis ofrotation.
 2. A vehicle, comprising: an engine disposed on the vehicle,the engine having an output driving a transmission disposed on thevehicle, wherein the transmission powers at least one driven wheel todrive the vehicle; a gear drive assembly for driving powered equipment,the gear drive assembly disposed on the vehicle and comprising: aplurality of gears disposed in a housing; an input shaft powered by theengine and extending into the housing to engage and power a first gearof the plurality of gears, wherein the input shaft rotates along a firstaxis of rotation; an output shaft having a second axis of rotation thatis perpendicular to the first axis of rotation, wherein the output shafthas opposite ends that are accessible from opposite sides of the housingto drive the powered equipment; and a support shaft for a second gear ofthe plurality of gears, the support shaft having a longitudinal axisthat is perpendicular to both the first axis of rotation and the secondaxis of rotation.
 3. The vehicle of claim 2, wherein the poweredequipment comprises an auger.
 4. The vehicle of claim 2, furthercomprising a belt and pulley system driven by the engine output, whereinthe belt and pulley system powers both the transmission and the inputshaft of the gear drive assembly.
 5. The vehicle of claim 2, wherein thefirst gear comprises a pinion bevel gear, which is engaged to and drivesa domed bevel gear, and the first gear and the domed bevel gear comprisea first stage gear reduction.
 6. The vehicle of claim 5, wherein thedomed bevel gear comprises a central opening, and the second gear isdisposed in the central opening.
 7. The vehicle of claim 6, wherein theplurality of gears further comprises an output bevel gear splined to theoutput shaft, and the second gear and the output bevel gear form asecond stage gear reduction.
 8. The vehicle of claim 2, wherein a firstend of the output shaft extends through a first output shaft opening onone side of the housing and a second end of the output shaft extendsthrough a second output shaft opening on a second side of the housing.9. The vehicle of claim 8, wherein the output shaft comprises a tubularoutput shaft and the plurality of gears further comprises an outputbevel gear splined to the tubular output shaft.
 10. A vehicle,comprising: an engine disposed on the vehicle; a transmission disposedon the vehicle and driven by the engine, wherein the transmission powersat least one driven wheel of the vehicle; a separate drive assembly fordriving powered equipment disposed on the vehicle, the drive assemblycomprising: a housing comprising a main housing member having a firstoutput shaft opening formed therein and a cover fastened to the mainhousing member, the cover having a second output shaft opening formedtherein; a gear drive disposed in the housing and comprising a pluralityof gears; an input shaft having a first end extending into the housingand engaged to and powering the gear drive and a second end powered bythe engine, wherein the input shaft has a first axis of rotation; anoutput shaft powered by the gear drive and having a second axis ofrotation that is perpendicular to the first axis of rotation, wherein afirst end of the output shaft is accessible through the first outputshaft opening in the main housing member and a second end of the outputshaft is accessible through the second output shaft opening in thecover; and a support shaft for one of the plurality of gears, thesupport shaft having a longitudinal axis that is perpendicular to thefirst axis of rotation and the second axis of rotation.
 11. The vehicleof claim 10, further comprising at least one tab formed on an internalsurface of the cover adjacent to the second output shaft opening. 12.The vehicle of claim 10, wherein the powered equipment comprises anauger.
 13. The vehicle of claim 10, wherein the gear drive furthercomprises a first gear disposed on and driven by the input shaft, asecond gear driven by the first gear, a third gear driven by the secondgear and disposed on the support shaft, wherein the second gear and thethird gear have a common axis of rotation, and a fourth gear driving theoutput shaft, wherein the fourth gear is driven by the third gear. 14.The vehicle of claim 13, wherein the fourth gear drives the output shaftby means of a key formed on the output shaft.
 15. The vehicle of claim14, wherein a first end of the output shaft extends through the firstoutput shaft opening in the main housing member and a second end of theoutput shaft extends through the second output shaft opening in thecover.
 16. The vehicle of claim 13, wherein the first gear comprises apinion bevel gear, which is engaged to and drives a domed bevel gear,and the first gear and the domed bevel gear comprise a first stage gearreduction.
 17. The vehicle of claim 16, wherein the domed bevel gearcomprises a central opening, and the second gear is disposed in thecentral opening.
 18. The vehicle of claim 17, wherein the fourth gearcomprises an output bevel gear splined to the output shaft, and thesecond gear and the output bevel gear form a second stage gearreduction.
 19. The vehicle of claim 10, further comprising a belt andpulley system driven by an engine output shaft, wherein the belt andpulley system powers both the transmission and the input shaft of thedrive assembly.